The assistance is legal, but civil liberties groups and Arab-American advocacy organizations say it is a dangerous breach of public trust and liken it to the Census Bureau's compilation of similar information about Japanese-Americans during World War II.

The tabulations were produced in August 2002 and December 2003 in response to requests from what is now the Customs and Border Protection division of the Department of Homeland Security. One set listed cities with more than 1,000 Arab-Americans. The second, far more detailed, provided ZIP-code-level breakdowns of Arab-American populations, sorted by country of origin. The categories provided were Egyptian, Iraqi, Jordanian, Lebanese, Moroccan, Palestinian, Syrian and two general categories, 'Arab/Arabic' and 'Other Arab.'…"

Census tabulations of specialized data are legal as long as they do not identify any individual.

Christiana Halsey, a spokeswoman for Customs and Border Protection, said the requests were made to help the agency identify in which airports to post signs and pamphlets in Arabic. "The information is not in any way being used for law enforcement purposes," she said. "It's being used to educate the traveler. We're simply using basic demographic information to help us communicate U.S. laws and regulations to the traveling public."

But critics of the information sharing said general demographic snapshots could be derived without such detailed information and that the ZIP-code-level data with its breakdowns of ancestral origin seemed particularly excessive because for all of the groups only English or Arabic need be used.

"The real question is to Homeland Security," said Samia El-Badry, an Arab-American member of the Census Bureau's decennial census advisory committee. "What are they hiding? Why do they need this?"

James Zogby, president of the Arab American Institute, said the data sharing was particularly harmful at a time when the Census Bureau is struggling to build trust within Arab-American communities. "As this gets out, any effort to encourage people to full compliance with the census is down the tubes," Mr. Zogby said. "How can you get people to comply when they believe that by complying they put at risk their personal and family security?"

In 2000, the bureau issued a formal apology for allowing its statistical data to be used to round up Japanese-Americans for internment during World War II.…

About Me

I'm sixty, and for good or ill the civil rights movement and the Viet Nam war are seared into the center of who I am. I graduated from Public School in Chicago, and went to Phillips Academy at Andover, like G.W. Bush, like Bremer, "Scooter" Libby was a classmate ('68). I was pro war in Viet Nam until Christmas Vacation of '67. I was watching the news and an Army Captain was describing how they'd trapped some Viet Cong in a tunnel. When no one would come out, they bulldozed earth over the air vents. Then some hours later they started pulling bodies out of the tunnel, all women and children. It was the first and only time I ever threw up watching the news, but I've come close since then.